WASHINGTON (CNN) --Items packed in a steamer trunk -- intended for Halloween costumes, said the trunk's owner -- set off airport explosive detection systems Thursday, causing a bomb scare and delays for passengers at West Palm Beach Airport in Florida.

The steamer trunk was one of two pieces of luggage passenger Eric Valleca, a 28-year-old Florida resident, checked on a United flight from West Palm Beach to Chicago, airport officials said.

Officials said the trunk set off the alarm, and X-rays showed several suspicious items, including radios, distributor caps attached to wires, batteries, PVC pipe painted black, stereo speakers and an alarm clock.

The trunk was removed from the terminal and taken to a "threat containment center," according to Palm Beach Airport sheriff's office spokesman Paul Miller.

Officials initially considered blowing the trunk up, but sent in a robot to take a closer look first.

Meanwhile, Valleca was taken off the plane and questioned by authorities.

The United flight he was on was delayed 45 minutes, and then took off without him.

Valleca explained to officials that he was going to use the packed items to dress up as characters from the movie "Ghostbusters."